Buggy code:
private Color [ ] secondaryLanguageBackgrounds ; public RSyntaxTextArea ( ) { } public RSyntaxTextArea ( RSyntaxDocument doc ) { } public RSyntaxTextArea ( String text ) { } public RSyntaxTextArea ( int rows , int cols ) { } public RSyntaxTextArea ( String text , int rows , int cols ) { } public RSyntaxTextArea ( RSyntaxDocument doc , String text , int rows , int cols ) { } public RSyntaxTextArea ( int textMode ) { } public void addActiveLineRangeListener ( ActiveLineRangeListener l ) { } public void addHyperlinkListener ( HyperlinkListener l ) { } @ Override public void addNotify ( ) { } public void addParser ( Parser parser ) { } protected void appendFoldingMenu ( JPopupMenu popup ) { } private void calculateLineHeight ( ) { } public void clearParsers ( ) { } private TokenImpl cloneTokenList ( Token t ) { } @ Override protected void configurePopupMenu ( JPopupMenu popupMenu ) { } public void copyAsRtf ( ) { } @ Override protected Document createDefaultModel ( ) { } @ Override protected RTAMouseListener createMouseListener ( ) { } @ Override protected JPopupMenu createPopupMenu ( ) { } private static void createRstaPopupMenuActions ( ) { } @ Override protected RTextAreaUI createRTextAreaUI ( ) { } protected final void doBracketMatching ( ) { } @ Override protected void fireCaretUpdate ( CaretEvent e ) { } private void fireActiveLineRangeEvent ( int min , int max ) { } private void fireHyperlinkUpdate ( HyperlinkEvent e ) { } void fireMarkedOccurrencesChanged ( ) { } void fireParserNoticesChange ( ) { } public void foldToggled ( Fold fold ) { } public void forceReparsing ( int parser ) { } public boolean forceReparsing ( Parser parser ) { } public boolean getAnimateBracketMatching ( ) { } public boolean getAntiAliasingEnabled ( ) { } public Color getBackgroundForToken ( Token token ) { } public boolean getCloseCurlyBraces ( ) { } public boolean getCloseMarkupTags ( ) { } public static synchronized CodeTemplateManager getCodeTemplateManager ( ) { } public static final Color getDefaultBracketMatchBGColor ( ) { } public static final Color getDefaultBracketMatchBorderColor ( ) { } public static Color getDefaultSelectionColor ( ) { } public SyntaxScheme getDefaultSyntaxScheme ( ) { } public boolean getEOLMarkersVisible ( ) { } public FoldManager getFoldManager ( ) { } public Font getFontForTokenType ( int type ) { } public FontMetrics getFontMetricsForTokenType ( int type ) { } public Color getForegroundForToken ( Token t ) { } public Color getForegroundForTokenType ( int type ) { } public boolean getFractionalFontMetricsEnabled ( ) { } private final Graphics2D getGraphics2D ( Graphics g ) { } public boolean getHighlightSecondaryLanguages ( ) { } public Color getHyperlinkForeground ( ) { } public boolean getHyperlinksEnabled ( ) { } public int getLastVisibleOffset ( ) { } @ Override public int getLineHeight ( ) { } public LinkGenerator getLinkGenerator ( ) { } public List < DocumentRange > getMarkAllHighlightRanges ( ) { } public List < DocumentRange > getMarkedOccurrences ( ) { } public boolean getMarkOccurrences ( ) { } public Color getMarkOccurrencesColor ( ) { } boolean getMarkOccurrencesOfTokenType ( int type ) { } public Color getMatchedBracketBGColor ( ) { } public Color getMatchedBracketBorderColor ( ) { } Rectangle getDotRectangle ( ) { } Rectangle getMatchRectangle ( ) { } @ Override public int getMaxAscent ( ) { } public boolean getPaintMatchedBracketPair ( ) { } public boolean getPaintTabLines ( ) { } public Parser getParser ( int index ) { } public int getParserCount ( ) { } public int getParserDelay ( ) { } public List < ParserNotice > getParserNotices ( ) { } public int getRightHandSideCorrection ( ) { } public boolean getShouldIndentNextLine ( int line ) { } public String getSyntaxEditingStyle ( ) { } public SyntaxScheme getSyntaxScheme ( ) { } public Color getTabLineColor ( ) { } public boolean getPaintMarkOccurrencesBorder ( ) { } public Color getSecondaryLanguageBackground ( int index ) { <START_BUG> return secondaryLanguageBackgrounds [ index ] ; <END_BUG> } public int getSecondaryLanguageCount ( ) { } public static synchronized boolean getTemplatesEnabled ( ) { } private Token getTokenListFor ( int startOffs , int endOffs ) { } public Token getTokenListForLine ( int line ) { } TokenPainter getTokenPainter ( ) { } @ Override public String getToolTipText ( MouseEvent e ) { } protected String getToolTipTextImpl ( MouseEvent e ) { } public boolean getUnderlineForToken ( Token t ) { } public boolean getUseFocusableTips ( ) { } public boolean getUseSelectedTextColor ( ) { } @ Override protected void init ( ) { } public boolean isAutoIndentEnabled ( ) { } public final boolean isBracketMatchingEnabled ( ) { } public boolean isClearWhitespaceLinesEnabled ( ) { } public boolean isCodeFoldingEnabled ( ) { } public boolean isWhitespaceVisible ( ) { } public Token modelToToken ( int offs ) { } @ Override protected void paintComponent ( Graphics g ) { } private void refreshFontMetrics ( Graphics2D g2d ) { } public void removeActiveLineRangeListener ( ActiveLineRangeListener l ) { } public void removeHyperlinkListener ( HyperlinkListener l ) { } @ Override public void removeNotify ( ) { } public boolean removeParser ( Parser parser ) { } public void restoreDefaultSyntaxScheme ( ) { } public static synchronized boolean saveTemplates ( ) { } public void setActiveLineRange ( int min , int max ) { } public void setAnimateBracketMatching ( boolean animate ) { } public void setAntiAliasingEnabled ( boolean enabled ) { } public void setAutoIndentEnabled ( boolean enabled ) { } public void setBracketMatchingEnabled ( boolean enabled ) { } public void setClearWhitespaceLinesEnabled ( boolean enabled ) { } public void setCloseCurlyBraces ( boolean close ) { } public void setCloseMarkupTags ( boolean close ) { } public void setCodeFoldingEnabled ( boolean enabled ) { } private final void setDefaultAntiAliasingState ( ) { } @ Override public void setDocument ( Document document ) { } public void setEOLMarkersVisible ( boolean visible ) { } @ Override public void setFont ( Font font ) { }

Fix:
return secondaryLanguageBackgrounds [ ( index - 1 ) ] ;